Crimping



Feb. 28, 1961 R. K, STANLEY E-r AL 2,972,798

CRIMPING Filed Jan. 25, 1957 1 O /8 25 2 9 i ihr-25 25 /7 .ffl /7 /7gffg# 5 milf 36/6 576 36 V 9 3435 gel @I2 6 6 I v /2 'U1 2C n" 42 36'6gl: /3 3%/3 l' 26 la?" qu 6 f; 23 /6 1|; -l 212 1|@ 24 4'- V 4 4 22# 2z*8 l 28 e' 8 '1| 7 I "23 ll 3 INVENTORS ROBERT l( STANLEY IRA 6 CHWA R TZATrRNEY acity and other desirable characteristics.

United States Patent CRIMPING Filed Jan. 2s, 1951, ser. No. 635,845 sclaims. (c1. zs-rz) This invention relates to crimping of filamentaryarticles of polymeric organic composition, usually in the form ofcontinuous multifilament, hereinafter referred to simply as textilestrands, for manufacture into fabrics of woven, knit, or otherconstruction useful for textile or industrial applications.

Fabrics made up of rectilinear smooth-surfaced textile strands,especially those composed of material having hydrophobiccharacteristics, are unpleasantly slick to the touch, usually highlytranslucent, and lacking in bulk and covering power. Although thesedefects can be alleviated by conversion of the filaments into acontinuoustructure of staple fibers or by other physical or chemicaltreatment, subjection of the strand to a crimping operation precludesnecessity for the complex and time-consuming steps of staple formationand gives products exhibiting high ten- As here (and usually)understood, crimping denotes the more or less permanent deviation of astrand, whether filament by filament or as a group of filaments, as fromthe substantial rectilinearity of its customary as-producedconfiguration. The deviation or crimp may be either periodic oraperiodic, depending upon the method employed, as is well known in theart. It generally is accepted that synthetic filaments of almost anycomposition can be crimped somehow or other, although for obviousreasons the various thermoplastic compositions have proved especiallyameuable to crimping. Depending upon the process employed, the resultingcrimp configuration may exhibit undesirable regularity or extremeirregularity, the crimp frequency may be insufficient, or the crimp maybe characterized by annoying residual torque or helical liveiiness inthe strand; barr and other irregularities may result in fabric scomposed.

A primary object of the present invention is improvement incharacteristics of twist-crimped textile strands and of fabrics composedof them. An object is certain compound or multiplie crimping of textilestrands to overcome undesirably regular crimp characteristics. Aparticular object is elimination of residual torque from strands havinga helical crimp. Other objects of this invention, together with meansand methods for attaining the various objects, will be apparent from thefollowing description and the accompanying diagrams.

Fig. 1 is a schematic or block diagram indicating practice of thepresent invention as an adjunct to existing practice. Fig. 2A is a frontelevation (partially cut away), Fig. 2B a side elevation, and Fig. 2C ahorizontal section (taken at 2C-2C of Fig. 2B) of a form of apparatusfor practicing the present invention. Fig. 3A is a side elevation of amultifilament textile strand before crimping; Fig. 3B is a view of thisstrand after performance of a first crimping operation upon it; and Fig.3C is a like vicw of the same strand after further crimping according tothis invention.

In general, the objects of the present invention are accomplished in atextile strand by supermposing an irregular crimp configuration upon anexisting crimp con- 21,972,798 Patented Feb. 28, 1981 gurationcharacterized by undesirable regularity of direction, frequency, or thelike. The invention contemplates performance of this by continuouslyfeeding a regularly crimped textile strand into a confining chamber,thereby modifying the crimp configuration of the strand, and withdrawingthe strand with modified crimp configuration from the confining chamber,especially without necessity for externally appliedv heat. Particularlycomprehended in the filamentary materials upon which this process ishighly effective are textile strands that exhibit a helical liveliness,inasmuch as the present crimping operation is effective -to inhibit thatlivelness while also imparting additonal desired characteristics to thestrand.

Fig. 1 shows (diagrammatically) uncrimper strand 10 entering firstcrimper 1 to emerge as crimped strand 20; this crimped strand thenenters second crimper 2, in which further crimping is accomplishedaccording to the present invention, strand 30 being the resultant.

Figs. 2A, 2B, and 2C show in front elevation, side elevation, andsectional plan, respectively, one form of stutter-crimper" capable ofsatisfying the requirements for the second crimper of Fig. 1. Thiscrimper, which is of a general type well known in the art, has as itsprincipal supporting parts base or bottom plate 11 and top plate 12extending horizontally, front plate or facade 13 extending verticallyfrom the bottom plate to and above the top plate, and back plate 23joining the bottom and top plates at the rear. Also prominent are pair0f stuffer rolls 4, 4', located side by side in front of the facadebetween the two horizontal plates, and crimping tube 5 extending fromabove the nip of the stuffer rolls to a level well above the top of thefacade. Four wingnuts 6, threaded on studs 36 extending from the facade,retain washers 16 against the front of the tube to hold it in placeagainst the front of the facade, with the saddleshaped lower end of thetube (shown in broken lines) closely approaching the roll nip.

The top of the tube is closed by cover 15 pivotally affixed by dependingear 18 to pin 29 on the exterior wall of the tube, and the cover isurged downwardly "ice against the top of the tube by springs 25, 25affixed at 17' and at the upper end to the cover by pins 19, 19'.located near the top of the tube opposite the front of the cover. Drivemotor 9 is mounted on the top plate, and shaft 34 extends rearward fromthe motor and through journal 35 upstanding from the back plate. Themotor shaft carries drive pulley 32, about which drive belt 26 passes.The drive belt also passes about pulley 24 on shaft 22, which extendsrearward from feed roll 4 affixed to the shaft. As shown in Fig. 2C,gear 28 on shaft 22 meshes with like gear 28' on shaft 22', whichextends rearward from feed roll 4' mounted on it. The strand itself isomitted from this latter view for simplicity of the. representation.

Initially crimped strand 20 passes upward from the source of supply (notshown) located below the illustrated apparatus, passes over feed block 7secured to the facade by screw 38 and under overlying clip 8 attached byscrew 37 into the side of the block, both located just below the rollnip to form an entering or infeeding guide, and the strand then passesthrough the nip of the counterrotating stufier rolls and into theclose-fitting lower end of the crimping tube. Part of the tube is cutaway in Fig. 2A to reveal the accumulation of yarn stuffed up throughthe bore of the tube. The cover provides back pressure effective toimpede exit of crimped strand 30 from the tube. Thus, the strand(filling the tube) bends back and forth and from side to side as it isstuffed into the bottom end of the tube, these various deviations fromthe original configuration of the strand being emphasized under theapplied back pressure to the extent of becoming a relatively permanentcrimp.

The actual crimping occurs essentially as is customary in this generaltype of crimper, other forms of which are disclosed in the followingU.S. patents, inter alia: 2,311,174 -to I. V. Hitt; 2,715,309 to N.Rosenstein et al.; 2,734,228 to W. D. Hay; and in U.S. patentapplication, Serial No. 624,613, filed November 27, 1956, by Ralph W.List and Ira Schwartz, in which passage of the crimped yarn accumulationthrough an open-ended crimping tube is impeded by a unidirectionallyrotatable gear or similar element intercepting the bore of the tube atleast partially.

Any of the following well-known crimping devices and l procedures may beemployed to impart the initial crimp, i.e., to convert simplemultiflament strand 10 to singly crimped multiflament strand 20: thedevices and procedures illustrated in U.S. Patents 2,111,209 and2,216,810 to H. Dreyfus; 2,089,198, 2,089,199, 2,089,200 and 2,- 111,211to D. Finlayson et al.; 2,089,239 to W. Whitehead; 2,463,619 to A.Kunzle; and 2,463,620 and 2,655,- 781 to G. Heberle'in. The immediateproducts of these crimping techniques and apparatus exhibit undesirablerecurrence or regularity of crimp, which can be alleviated according tothe present invention while retaining many of the benefits of thatinitial crimp or even enhancing them and endowing the strand withfurther desirable characteristics.

An especially undesirable feature of twist-crimped strands is theresidual torque or helical liveliness exhibited by them as a result ofthe twisting (or false-twisting) to which they were subjected, usuallyaccompanied by setting and followed by purported elimination of thetwist. The unbalance of such lively strands conventionally is balancedby plying (strands of opposite twists) or by other well-known techniquesto prevent unwanted distortion of garments and other articles socomposed. The present invention is especially adapted to elimination orminimization of that liveliness, usually at the same time imparting acloser but more nearly random crimp to the component filaments, tworesults that in many respects appear contrary and either of which wasunpredictable.

Fig 3A represents the lateral appearance of strand 10 of continuousfilaments, the filaments lying in substantial rectilinear alignment, asproduced by any of the many well-known methods. Fig. 3B representscorresponding strand 20 having an initial crimp, preferably imparted toit by one of the regular false twisting methods; while it has becomeshorter than the uncrimped strand, no attempt is made in the drawing tosuggest the change in length imparted by the crimping. Noticeable areboth a periodic or recurrent undulation of the strand as a hole and ashorter wavy crimp in the individual filaments, this configuration beingindicative of the previously mentioned helical liveliness.

Fig. 3C shows strand 30, which corresponds to previous strand 20 after asecond crimping, as indicated above. The outline is more uniform, thecrimp spacing closer but less regular, and the interlament spacinggreater, with the result that this strand is bulkier or loftier. Littleor no trace remains of the phased multilament undulation visible instrand 20, and the helical liveliness is likewise absent. In general,twist-crimped strands subsequently stuffer-crimped according to thisinvention exhibit a greater degree of recovery to the crimped lengthafter removal of extensional force than characterized the initiallytwist-crimped strands (or, for that matter, conventional stutfer-crimpedspecimens); this is the more surprising inasmuch as the highcrimp-elasticity of twist-crimped (i.e., strand-extensibility withoutactual stretching of the component filaments) is greatly reduced asexpected, by the stuffing step.

These striking transformations in the strand are carried over intofabric composed thereof, to endow it with characteristics considerablydifferent from those of fabrics composed of regular twist-crimpedstrands (inherently unbalanced) or of the uncrimped multifilament(notably slick and translucent). In loftiness and covering power suchfabric is fully the equivalent of or superior to that produced fromcontinuous-filament strands subjected to the complex and expensiveprocedure of hot stuffer-crimping, one feature of the present inventionbeing the freedom of the prescribed stuffer-crimping step from thenecessity of applying heat from the outside; of course, heat may beapplied if desired, although it actually may be deleterious to theinitial or preceding crimp. The many procedural advantages andproduct-wise benefits of this invention will become fully apparent tothose undertaking to practice it in its entirety.

The claimed invention:

1. Process of treating a twist-crimped textile strand of continuousfilaments to alter its configuration of crimp, increase itscrimp-recovery, and substantially eliminate its helical liveliness,comprising subjecting it on the run to a stutfer-crimping operation.

2. Crimped strand produced by the process of claim 1 and exhibiting, ascompared with the strand before being so treated, increasedcrimp-recovery, substantial lack of helical liveliness, and decreasedcrimp-elasticity.

3. Process of treating a textile strand of continuous filamentscomprising the steps of twist-crimping such a strand to give it aregular helical crimp, and crimping said twist-crimped strand to modifythe regular helical crimp by superimposing thereon a haphazard crimpwith a random distribution of crimp angle.

References Cited in the file of this patent UNITED STATES PATENTS2,647,285 Pfau Aug. 4, 1953 2,715,309 Rosenstein et al Aug. 16, 19552,865,080 Hentschel Dec. 23, 1958 FOREIGN PATENTS 595,634 Great BritainDec. 1l, 1947 682,263 Great Britain Nov. 5, 1952 OTHER REFERENCES DuPont Technical Information Bulletin N-56, page 23, February 1956, E. I.Du Pont De Nemours & Co., Wilmington, Del. (Copy in Division 21, U.S.Patent Office.)

R. W. Moncrief, Artificial Fibers, page 409; John Wiley & Sons, Inc.;New York, N.Y.; 1954. (Copy in Division 21, U.S. Patent Omce.)

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No.2,972,798 February 28, 1961 Robert K. Stanley et al.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below'.

Column l, line 52, for "multiplie" read multiple column 2, line l5, for"uncrmper" read uncrmped column 3, line 49, for "false twisting" readfalse-twisting line 54, for "hole" read whole column 4, line 9,

Signed and sealed this 18th day of July 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner ofPate-nts UNITED STATES PATENT oEEIeE CERTIFICATION OF CORRECTION PatentNo., 2,972,798 February 28, l9l

Robert K. Stanley et al.

It is hereby certified that error appears n the above numbered patentrequiring Correction and that the said Letters Patent should read asCorrected below'.

Column l, line 52, for "multiplie" read multiple column 2, line l5, for"uncrmper" read uncrmped column 3, line 49, for "false twisting" readfalse-twisting line 54, for "hole" read whole column 4, line 9, after"twist-crimped insert strands signed and sealed this 18th day of July-1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

